The present invention relates to a resealable label flap positionable to cover an opening in a product package containing removable articles such that the label flap can be repeatedly removed and reapplied to access the articles contained within the package. More specifically, the present invention relates to a resealable label flap that includes a tamper evident tab having a printed indicia that separates from the remaining portions of the label flap and remains attached to the product package after the label flap is removed from the product package for the first time.
Resealable label flaps are commonly used with product packages that include packaged sheet-like removable articles that have been thoroughly wetted with a liquid prior to packaging. The product package is generally constructed from a thin, liquid impervious material that has an opening over which the label flap is removably adhered. Typically, the label flap is a strip of flexible or semi-rigid thermoplastic material having a removable pressure-sensitive adhesive applied to one surface of the label. The removable adhesive creates a generally air-tight seal around the package opening to prevent the packaged removable articles from drying out during storage.
Since resealable label flaps can be continuously removed and reapplied to the product package containing removable articles without any indication that the product package has been previously opened, a need has arisen for a resealable label flap that provides an indication that the product package has been opened and subsequently resealed. Particularly, a need exists for such a tamper evident resealable label flap in the medical field, since once the product package has been opened, the contents of the product package may no longer be sterile.
Therefore, it is an object of the present invention to provide a resealable label flap that includes means for indicating whether the label flap has previously been removed from the product package. It is an additional object of the invention to provide a resealable label flap that includes a tamper indicating tab formed on the label flap that separates from the label flap and remains attached to the product package when the label flap is initially removed from the package. It is a further object of the invention to provide a discontinuous first ink layer on the tamper indicating tab that defines an indicia and a second ink layer that covers the first ink layer such that the indicia is not visible when the label flap is initially applied to the product package. It is a further object of the present invention to provide the second ink layer that has desired adhesive properties such that the second ink layer adheres to the top layer of the label flap and separates from the first ink layer when the label flap is initially removed from the product package, thereby allowing the indicia created by the first ink layer to be visible when the label flap is removed. It is a further object of the present invention to position the tamper indicating tab on a starting tab formed on the label flap such that the tamper indicating tab separates from the label flap prior to the label flap being pulled past the opening in the product package. Additionally, it is an object of the present invention to provide an easily constructed, and easily printed tamper evident resealable label flap that can be used in connection with a product package to accurately indicate whether the product package has been previously opened.
The present invention is a resealable label flap that can be positioned to cover an opening in a product package. The resealable label flap includes a main body portion extending between a first end and a second end. The main body portion includes a generally smooth top surface and a bottom surface including a layer of a first adhesive. The first adhesive is applied over the entire bottom surface of the main body portion and is a removable pressure-sensitive adhesive that retains its adhesive properties following repeated removal and reapplication of the main body portion to the package body.
The label flap further includes a starting tab integrally formed with the main body portion and positioned adjacent to one end of the main body portion. The first adhesive is rendered ineffective on the starting tab such that the starting tab does not adhere to the top surface of the package body when the label flap is applied to the product package.
The label flap is a two layer construction consisting of a base layer and a transparent top layer adhesively attached to the base layer. Prior to attachment of the transparent top layer to the base layer, a tamper indicating tab is formed in the base layer. The tamper indicating tab is defined by a weakened portion of the base layer such that the tamper indicating tab can be separated from the remaining portions of the base layer. In the preferred embodiment of the invention, the tamper indicating tab is a die cut shape formed as part of the starting tab.
The tamper indicating tab includes the first adhesive applied to its bottom surface. When the label flap is applied to the package body, the layer of first adhesive applied to the bottom surface of the tamper indicating tab forms an adhesive bond between the tamper indicating tab and the top surface of the package body. The adhesive bond between the first adhesive on the bottom surface of the tamper indicating tab and the top surface of the package body is stronger than the strength of the weakened area of the base layer defining the tamper indicating tab such that when the label flap is initially removed from the package body, the tamper indicating tab separates from the remaining portions of the starting tab.
Prior to the tamper indicating tab being formed in the base layer, a first ink layer is printed to the top surface of the base layer in the area that will form the tamper indicating tab. The first ink layer is a discontinuous layer of ink that defines an indicia on the top surface of the tamper indicating tab. The first ink layer forms a chemical bond to the top surface of the tamper indicating tab. Preferably, the first ink layer is of a light color and defines the indicia on the tamper indicating tab.
After the first ink layer has been applied, a second ink layer is applied over the entire tamper indicating tab, including the portion of the tamper indicating tab including the first ink layer. The second ink layer bonds to the top surface of the tamper indicating tab in the areas not covered by the first ink layer. The second ink layer is selected such that the second ink layer does not bond to the first ink layer in the areas in which the second ink layer is applied over the top of the first ink layer. In the preferred embodiment of the invention, the second ink layer is a dark color, such that the first ink layer is not visible through the second ink layer when viewed from above.
After the second ink layer has been applied over the tamper indicating tab, the tamper indicating tab is die cut and the transparent top layer is adhesively attached to the entire base layer, including the portion of the base layer upon which the first ink layer and the second ink layer were previously printed. After the top layer has been applied to the base layer, the entire label flap can be applied to the product package.
Once the label flap has been applied to the product package, the label flap can be removed by the user to access the disposable articles contained within the product package. As the label flap is pulled from the product package for the first time, the tamper indicating tab separates from the remaining portions of the label flap due to the adhesive bond created between the first adhesive contained on the bottom surface of the tamper indicating tab and the top surface of the product package. As the tamper indicating tab separates from the label flap, the first ink layer remains on the tamper indicating tab due to the chemical bond between the first ink layer and the tamper indicating tab. At the same time, the areas of the second ink layer printed directly onto the tamper indicating tab between the first ink layer also remain attached to the tamper indicating tab.
The types of ink used for the first ink layer and the second ink layer are specifically selected such that as the tamper indicating tab separates from the label flap, the areas of the second ink layer printed on the first ink layer separate from the first ink layer and remain attached to the top layer of the label flap. Specifically, the second ink layer is selected such that the second ink layer creates a stronger bond to the top layer of the label flap than the bond between the first ink layer and the second ink layer. Thus, once the label flap has been initially removed from the product package, the indicia defined by the first ink layer remains on the tamper indicating tab while the areas of the second ink layer printed over the first ink layer separate from the first ink layer to define the negative image of the indicia on the top layer of the label flap.
Once the label flap has been removed to reveal the opening in the product package, the label flap can be reapplied to the product package to seal the opening in the product package. As the label flap is reapplied to the package body, the negative image of the indicia on the label flap no longer lines up with the positive image of the indicia contained on the tamper indicating tab. Thus, the user is able to immediately determine that the product package has been previously opened due to the misalignment between the negative and positive images created by the first and second ink layers.
The tamper indicating tab can be formed either in the starting tab of the label flap or at various positions on the label flap. Both the separation of the tamper indicating tab from the label flap and the separation between the first and second ink layers allow the user to determine whether the label flap has been previously opened to prevent tampering to the articles contained in the product package.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.